fix(app): clamp virtualizer range to scroll bounds

[opencode-agent]

Summary

• Move the fix down into our @tanstack/virtual-core patch instead of special-casing the session timeline.
• Clamp the scroll offset used for range calculation to the real scrollable bounds (0...max(totalSize - viewportSize, 0)).
• This keeps bottom anchoring / initialOffset: Number.MAX_SAFE_INTEGER from producing an impossible end-of-list range when the browser has clamped a fit-to-viewport list to scrollTop = 0.

Validation

• bun install --frozen-lockfile
• bun typecheck from packages/app
• Local Playwright repro with a 5600px viewport: before the core clamp the session rendered 7 rows starting at index 50; after the clamp it rendered 57 rows from index 0 both initially and after Home → session tab.

Repro evidence

• Original before/after screenshots from the app-layer attempt are in the Discord debugging thread: before https://discord.com/channels/1391832426048651334/1521440168744062976/1521443052579979304 and after https://discord.com/channels/1391832426048651334/1521440168744062976/1521443054907687032.

[Copilot]

Pull request overview

This PR updates the repository’s @tanstack/virtual-core patch to clamp the scroll offset used for virtual range calculation to the actual scrollable bounds, preventing invalid “end-of-list” ranges when initialOffset is extremely large but the browser clamps scrollTop to 0.

Changes:

• Clamp scrollOffset to 0...max(totalSize - viewportSize, 0) before calling calculateRange.
• Apply the change consistently across the patched package’s src and built dist outputs.

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